In the machine processing of various types of information contained on tickets, tags, labels, postage imprints and the like it is generally known to employ detectors which are responsive to shape relationships and/or colors, and in many cases to the fluorescence of an ink which may be excited, for example, by ultraviolet light. Fluorescent inks and dyes have long been known as, for example, those disclosed in U.S. Pat. Nos. 2,681,317; 2,763,785; 3,230,221; 3,412,104; 3,452,075; and 3,560,238. The fluorescent inks and the methods of making or using them as known in the prior art, generally entail the use of a fluorescent ink which, when irradiated, will fluoresce and emit radiation within the wavelength for the particular fluorescent color of that dye or ink. It is known, for example, in the postage meter art to provide a red fluorescent ink for machine reading of processed mail.
The fluorescent detectors, however, are generally designed or set to pick up emissions only within a certain range of wavelengths and accordingly, the coloration of the ink will be dependent upon the formulation which provides for fluorescence under light such as ultraviolet light, to emit radiation of a certain wavelength.
It is desirable, however, to provide tickets, tags, labels, postage meter imprints, stampings, or the like with a greater variety of visual color for classification, for inventory purposes or sorting, for example, so that the tags, tickets, envelopes and the like are, or may be, processed visually by people, as well as by one or more machines. A problem arises, however, when a variety of visual colors are used since the visual color is generally related to the fluorescent color of the ink when it is irradiated. Thus, if there is a mixture of different tags, tickets, or letters which are to be machine read, the machine must be responsive to a broad spectrum of emission wavelengths or the machine must be adjusted to receive the wavelengths of the various fluorescent ink colors as they are processed.
Accordingly, it is an object of the invention to provide means for having two different colors contained in the same ink, one an ordinary mixed light color and the other a fluorescent color.
Other objects of the invention will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises a method and a composition of matter possessing the characteristics, properties, and the relation of components which will be exemplified in the composition and the method of use thereof hereinafter described, and the scope of the invention will be indicated in the claims.